1. Field of the Invention
The invention relates to a fluid control valve having an axially reciprocating valve shaft on which is mounted a valve body that seals and unseals a passage within a fluid flow path; and, more particularly to a fluid control valve with a shaft guide for retarding or dampening reciprocation-induced vibrations.
2. Related Art
Fluid control valves are well known and are generally solenoid-actuated valves wherein a solenoid moves a valve shaft on which is mounted a valve body to bring the valve body into and out of contact with a valve seat within a fluid path to control the flow of fluid through the fluid path. Solenoid-actuated fluid control valves are often used to control the air in a bypass line around a throttle valve in an internal combustion engine for an automobile to improve the idle performance. The solenoid-actuated valve controls the flow of fluid between the atmospheric or high pressure side of the throttle valve and the low pressure or suction side of the throttle valve. At certain operational conditions, the engine can require a greater volume of air than can be passed through the throttle valve without increasing engine rpm. In these instances, the control valve opens the throttle valve bypass passage to permit increased air flow to the engine. The bypass passage and valve reduces the engine""s tendency to otherwise continuously raise and lower the rpm to adjust the air flow, which is referred to as xe2x80x9csearching.xe2x80x9d U.S. Pat. No. 4,360,161, issued Nov. 23, 1982, and U.S. Pat. No. 5,188,073, issued Feb. 23, 1993, are examples of this type of solenoid-actuated valve.
One particular problem associated with this type of solenoid-actuated valve is that the reciprocation of the shaft can induce shaft vibrations that can prevent the valve body from properly sealing with respect to the valve seat, resulting in unintended fluid flow between the high pressure and low pressure sides of the throttle valve. U.S. Pat. No. 5,188,073 discloses various spring designs for applying a transverse force directly to the valve shaft to dampen the reciprocation-induced vibrations. One disadvantage of the various spring solutions is that the spring is typically metal and is biased into direct contact with the reciprocating shaft, resulting in increased wearing or abrading of the shaft.
There is still a desire and need to dampen the vibrations of the axially-reciprocating shaft without unnecessary or undue wear of the shaft.
The invention relates to a valve for controlling the flow of fluid through a conduit having an upstream portion with a first fluid pressure and a downstream portion with a second fluid pressure. The valve comprises a valve housing defining a fluid passage having an inlet adapted to be fluidly connected to the upstream portion of the conduit and an outlet adapted to be fluidly connected to downstream portion of the conduit. A valve seat is disposed within the fluid passage along with a first annular bearing located on the upstream side of the valve seat and a second annular bearing located on the downstream side of the valve seat.
The valve further includes a valve assembly comprising an elongated shaft having a first end slidably mounted within the first annular bearing and a second end slidably mounted with the second annular bearing for reciprocal movement within the passage along a longitudinal axis of the elongated shaft. A valve body is mounted on the shaft and moved into and out of contact with the valve seat in response to the reciprocation of the shaft to fluidly close the passage when the valve body contacts the valve seat and fluidly open the passage when the valve body is spaced from the valve seat.
A dampening mechanism dampens the vibration of the shaft and comprises a guide mounted to the valve housing and having an inner surface defining a sleeve opening that is axially aligned with the shaft longitudinal axis and circumscribing the shaft. A sleeve is mounted to the shaft and has an outer surface shaped to be slidaby received within the sleeve opening. The movement of the shaft in a direction transverse from the shaft longitudinal axis results in contact between at least a portion of the sleeve and a portion of the guide to thereby retard the movement of the shaft in a direction other than along the shaft longitudinal axis.
Preferably, one of sleeve inner surface and guide outer surface has a rib projecting therefrom and the other of the sleeve inner surface and guide outer surface has a grooved formed therein, wherein the rib is received within the groove and the rib contacts a portion of the groove when the shaft moves in a direction transverse to the shaft longitudinal axis. The ribs and grooves comprise multiple pairs.
The groove has opposed diverging side walls to define a open top for the groove in which the rib is received. The cross-sectional width of the open top is greater than the cross-sectional width of the rib at the open top when the rib is received within the groove. A bottom wall preferably connects the diverging side walls to define the groove with a cross-sectional profile having an increasing width from the open top to the bottom wall.
The rib preferably has a substantially constant-width cross-sectional profile. The width of the groove has a minimum width portion and the rib has a cross-sectional width less than the groove minimum width.
In another aspect, the invention relates to a valve for controlling the flow of fluid through a conduit having an upstream portion with a first fluid pressure and a downstream portion with a second fluid pressure. The valve comprises a valve housing defining a fluid passage having an inlet adapted to be fluidly connected to the upstream portion of the conduit and an outlet adapted to be fluidly connected to downstream portion of the conduit. A valve seat is disposed within the fluid passage.
A valve assembly comprising an elongated shaft is slidably mounted to the housing for reciprocal movement within the passage along a longitudinal axis of the elongated shaft. A valve body is mounted on the shaft and moved into and out of contact with the valve seat in response to the reciprocation of the shaft to fluidly close the passage when the valve body contacts the valve seat and fluidly open the passage when the valve body is spaced from the valve seat.
A dampening mechanism is provided and comprises a guide mounted to the valve housing and having an inner surface defining a sleeve opening axially aligned with the shaft longitudinal axis and circumscribing the shaft in combination with a sleeve mounted to the shaft and having an outer surface shaped to be slidaby received within the sleeve opening. One of sleeve inner surface and guide outer surface has a rib projecting therefrom and the other of the sleeve inner surface and guide outer surface has a grooved formed therein. The rib is received within the groove contacts a portion of the groove when the shaft moves in a direction transverse to the shaft longitudinal axis to thereby retard the movement of the shaft in a direction other than along the shaft longitudinal axis.